We report a rapid, microwave‐assisted route to boron–nitrogen co-doped carbon dots (B,N-CDs) from lactic acid using boric acid and urea as dopants, and their immobilization on fumed SiO2 to yield a fluorescent developing powder for latent fingerprints. The B,N-CDs exhibit a steep deep-UV absorption with a shoulder at ∼280–300 nm and a single blue photoluminescence band centered at ∼430 nm (λex = 310 nm). FT-IR reveals O–H/N–H, CO/CN and C–N vibrations together with B–O features, while XRD shows a broad turbostratic (002), evidencing small sp2 domains. High-resolution XPS resolves sp2 C–C/CC with C–O/CO surface groups, pyrrolic/graphitic N, and B–O, confirming successful B,N co-doping. After immobilization, SEM shows the native chain-like morphology of fumed silica retained, and EDS detects C and N alongside Si and O, corroborating surface coverage by B,N-CDs. The composite powder is off-white in daylight yet displays intense, uniform blue emission under 365 nm illumination. Applied to natural latent fingerprints on glass, the material affords clear ridge flow and minutiae under both white light and UV; AFIT analysis yields 50–52 minutiae per print with “good” scores. This environmentally conscious, 5-min synthesis coupled with silica immobilization delivers a stable, bright, and readily handled powder, demonstrating practical potential for high-resolution latent fingerprint visualization on non-porous substrates.
{"title":"Microwave-assisted synthesis of boron and nitrogen co-doped carbon dots immobilized on SiO2 nanoparticles for high-resolution latent fingerprint detection","authors":"Sutinee Girdthep , Soontorn Suvokhiaw , Sirirat Choosakoonkriang , Gulanat Chanachinrat , Cheewita Suwanchawalit","doi":"10.1016/j.optmat.2026.117919","DOIUrl":"10.1016/j.optmat.2026.117919","url":null,"abstract":"<div><div>We report a rapid, microwave‐assisted route to boron–nitrogen co-doped carbon dots (B,N-CDs) from lactic acid using boric acid and urea as dopants, and their immobilization on fumed SiO<sub>2</sub> to yield a fluorescent developing powder for latent fingerprints. The B,N-CDs exhibit a steep deep-UV absorption with a shoulder at ∼280–300 nm and a single blue photoluminescence band centered at ∼430 nm (λ<sub>ex</sub> = 310 nm). FT-IR reveals O–H/N–H, C<img>O/C<img>N and C–N vibrations together with B–O features, while XRD shows a broad turbostratic (002), evidencing small sp<sup>2</sup> domains. High-resolution XPS resolves sp<sup>2</sup> C–C/C<img>C with C–O/C<img>O surface groups, pyrrolic/graphitic N, and B–O, confirming successful B,N co-doping. After immobilization, SEM shows the native chain-like morphology of fumed silica retained, and EDS detects C and N alongside Si and O, corroborating surface coverage by B,N-CDs. The composite powder is off-white in daylight yet displays intense, uniform blue emission under 365 nm illumination. Applied to natural latent fingerprints on glass, the material affords clear ridge flow and minutiae under both white light and UV; AFIT analysis yields 50–52 minutiae per print with “good” scores. This environmentally conscious, 5-min synthesis coupled with silica immobilization delivers a stable, bright, and readily handled powder, demonstrating practical potential for high-resolution latent fingerprint visualization on non-porous substrates.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117919"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cesium iodide (CsI) is a wide-bandgap halide semiconductor with potential uses in radiation response and optoelectronics; nevertheless, its poor intrinsic conductivity restricts effective charge transfer. This study involved the deposition of granular CsI:Si layers on n-Si(100) substrates using magnetron sputtering and investigated their structural, optical, electrical, and initial radiation-response characteristics within a framework dominated by defects and interfaces in heterostructures. Grazing-incidence X-ray diffraction demonstrates texture evolution as well as considerable lattice compression with increased Si incorporation, alongside grain refinement and heightened compressive strain. Optical investigation of Kubelka–Munk-derived Tauc plots reveals several effective transitions linked to surface states, self-trapped excitons, and Vk centers, which demonstrate systematic alterations with the addition of silicon. Electrical experiments reveal that modest silicon incorporation improves percolative charge transport, but excessive incorporation results in transport deterioration. The current-voltage characteristics demonstrate rectification due to interfacial band bending and defect-assisted transport, aligning with thin-layer transport pathways. Preliminary circuit-level studies exhibit consistent signal modulation in response to visible light, γ-rays (Cs-137), and α-particles (Am-241). Despite constraints imposed by basic external electronic circuitry and material quality, these findings provide proof of concept that regulated silicon incorporation enables adjustable defect energetics and interfacial transport in cesium iodide-based heterostructures, thereby supporting future enhancements to integrated radiation-responsive and optoelectronic devices.
{"title":"Structural, optical, electrical, and radiation-response characteristics of sputtered granular CsI:Si layers on Si substrates","authors":"Rhett Simon Tabbada , Phannee Saengkaew , Dhanaj Saengchantr , Kamontip Ploykrachang , Sirasit Sreesai , Prutthipong Tsuppayakorn-aek , Tossaporn Lertvanithphol , Kittidhaj Dhanasiwawong , Mati Horprathum , Rawat Jaisutti","doi":"10.1016/j.optmat.2026.118006","DOIUrl":"10.1016/j.optmat.2026.118006","url":null,"abstract":"<div><div>Cesium iodide (CsI) is a wide-bandgap halide semiconductor with potential uses in radiation response and optoelectronics; nevertheless, its poor intrinsic conductivity restricts effective charge transfer. This study involved the deposition of granular CsI:Si layers on n-Si(100) substrates using magnetron sputtering and investigated their structural, optical, electrical, and initial radiation-response characteristics within a framework dominated by defects and interfaces in heterostructures. Grazing-incidence X-ray diffraction demonstrates texture evolution as well as considerable lattice compression with increased Si incorporation, alongside grain refinement and heightened compressive strain. Optical investigation of Kubelka–Munk-derived Tauc plots reveals several effective transitions linked to surface states, self-trapped excitons, and Vk centers, which demonstrate systematic alterations with the addition of silicon. Electrical experiments reveal that modest silicon incorporation improves percolative charge transport, but excessive incorporation results in transport deterioration. The current-voltage characteristics demonstrate rectification due to interfacial band bending and defect-assisted transport, aligning with thin-layer transport pathways. Preliminary circuit-level studies exhibit consistent signal modulation in response to visible light, γ-rays (Cs-137), and α-particles (Am-241). Despite constraints imposed by basic external electronic circuitry and material quality, these findings provide proof of concept that regulated silicon incorporation enables adjustable defect energetics and interfacial transport in cesium iodide-based heterostructures, thereby supporting future enhancements to integrated radiation-responsive and optoelectronic devices.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 118006"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147384887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A pioneering study of the thermo-optical properties of a terbium oxide crystal sample was undertaken. The linear absorption coefficient and thermal conductivity of the medium as well as the dependence of thermally induced phase and polarization distortions of transmitted radiation on its power were measured. The thermo-optical constants P and Q were estimated. It was shown that, due to the high Verdet constant and ξ = -0.1, the maximum operating power of the transmitted radiation of the studied material is several times higher than that of Tb2O3 ceramics with the same heat dissipation. This opens up broad prospects for its application in compact Faraday isolators for laser radiation of subkilowatt average power.
{"title":"Thermo-optical properties of terbium sesquioxide (Tb2O3). Part 2","authors":"A.V. Starobor , D.A. Kuzin , O.V. Palashov , R.E. Nikolaev , V.A. Trifonov , N.G. Naumov","doi":"10.1016/j.optmat.2026.117994","DOIUrl":"10.1016/j.optmat.2026.117994","url":null,"abstract":"<div><div>A pioneering study of the thermo-optical properties of a terbium oxide crystal sample was undertaken. The linear absorption coefficient and thermal conductivity of the medium as well as the dependence of thermally induced phase and polarization distortions of transmitted radiation on its power were measured. The thermo-optical constants <em>P</em> and <em>Q</em> were estimated. It was shown that, due to the high Verdet constant and <em>ξ = </em>-0.1, the maximum operating power of the transmitted radiation of the studied material is several times higher than that of Tb2O3 ceramics with the same heat dissipation. This opens up broad prospects for its application in compact Faraday isolators for laser radiation of subkilowatt average power.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117994"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A one-pot synthetic strategy was designed for the efficient and high-yield preparation of the aldehyde monomer, offering a simplified route to conjugated building blocks. This monomer was subsequently converted into three new π-conjugated materials through Horner–Wittig and Knoevenagel condensations. TD-DFT calculations were carried out to investigate their structural isomerism, revealing that the trans–trans configuration is the most stable for TDP-An and TDP-αCN-An, while the cis–cis configuration is favored for TDP-βCN-An. Incorporating nitrile (CN) groups into the vinylic backbone significantly influenced their thermal, optical, and electrochemical properties. UV-Vis absorption in thin films of TDP-An exhibited broadening and bathochromic shifts due to π–π stacking and aggregation. In contrast, hypochromic shifts were observed for TDP-αCN-An and TDP-βCN-An in solution, attributed to CN-induced torsion. Photoluminescence studies showed reduced quantum yields for CN-substituted materials, likely from enhanced non-radiative pathways. The introduction of cyano (–CN) groups also significantly influences the electronic gap (Eg) of conjugated systems through both steric and electronic effects. In TDP-αCN-An, the incorporation of –CN group induces steric repulsion, leading to torsion of the TDP–cyanovinyl bond (torsion ≈ 67°), thus reducing electronic delocalization and increasing Eg. This effect becomes more pronounced in TDP-βCN-An, where a stronger torsion (≈79°) occurs at the anthracene–cyanovinyl bond.
{"title":"CN-anthracene π-conjugated materials: cis/trans isomerization, and structure–property relationships via TD-DFT","authors":"Chaima Mahmoudi , Khouloud Baatout , Mustapha Majdoub , Nejmeddine Smida Jaballah","doi":"10.1016/j.optmat.2026.117974","DOIUrl":"10.1016/j.optmat.2026.117974","url":null,"abstract":"<div><div>A one-pot synthetic strategy was designed for the efficient and high-yield preparation of the aldehyde monomer, offering a simplified route to conjugated building blocks. This monomer was subsequently converted into three new π-conjugated materials through Horner–Wittig and Knoevenagel condensations. TD-DFT calculations were carried out to investigate their structural isomerism, revealing that the trans–trans configuration is the most stable for <strong>TDP-An</strong> and <strong>TDP-αCN-An</strong>, while the cis–cis configuration is favored for <strong>TDP-βCN-An</strong>. Incorporating nitrile (CN) groups into the vinylic backbone significantly influenced their thermal, optical, and electrochemical properties. UV-Vis absorption in thin films of <strong>TDP-An</strong> exhibited broadening and bathochromic shifts due to π–π stacking and aggregation. In contrast, hypochromic shifts were observed for <strong>TDP-αCN-An</strong> and <strong>TDP-βCN-An</strong> in solution, attributed to CN-induced torsion. Photoluminescence studies showed reduced quantum yields for CN-substituted materials, likely from enhanced non-radiative pathways. The introduction of cyano (–CN) groups also significantly influences the electronic gap (Eg) of conjugated systems through both steric and electronic effects. In <strong>TDP-αCN-An</strong>, the incorporation of –CN group induces steric repulsion, leading to torsion of the TDP–cyanovinyl bond (torsion ≈ 67°), thus reducing electronic delocalization and increasing Eg. This effect becomes more pronounced in <strong>TDP-βCN-An</strong>, where a stronger torsion (≈79°) occurs at the anthracene–cyanovinyl bond.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117974"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-02-17DOI: 10.1016/j.optmat.2026.117981
Manh Hoang Tran , Thi My Huyen Nguyen , Xuan Du Dang , Luan Minh Nguyen , Dieu Linh Tran , Dai Hai Nguyen
BaTiO3 (BTO) is a promising material for ultraviolet photodetectors (UV PDs) owing to its wide-bandgap larger than 3 eV, which is sensitive to UV spectra; and exceptionally high dielectric constant, which reduces the exciton binding energy and facilitates efficient free-carrier generation. However, its intrinsically low conductivity and defect-rich microstructure observed in the straightforward solution process hinder efficient charge transport in optoelectronic devices. To address these limitations, this study proposes a BTO:TiO2 composite film fabricated via a facile route. The role of TiO2 NPs tightly embedded within the BTO matrix as charge-transport “inter-bridges” was systematically elucidated in relation to film morphology and optoelectrical properties. The resulting BTO:TiO2 film exhibits reduced surface roughness, enhanced electron conductivity, and significantly improved UVB–C absorption, enabling its use as an efficient and stable photoabsorber for both narrow- and broadband UV photodetectors, thereby paving the way for numerous practical UV-sensing applications.
{"title":"TiO2 inter-bridges enable enhanced ultraviolet photodetection in BaTiO3 photoabsorbing films","authors":"Manh Hoang Tran , Thi My Huyen Nguyen , Xuan Du Dang , Luan Minh Nguyen , Dieu Linh Tran , Dai Hai Nguyen","doi":"10.1016/j.optmat.2026.117981","DOIUrl":"10.1016/j.optmat.2026.117981","url":null,"abstract":"<div><div>BaTiO<sub>3</sub> (BTO) is a promising material for ultraviolet photodetectors (UV PDs) owing to its wide-bandgap larger than 3 eV, which is sensitive to UV spectra; and exceptionally high dielectric constant, which reduces the exciton binding energy and facilitates efficient free-carrier generation. However, its intrinsically low conductivity and defect-rich microstructure observed in the straightforward solution process hinder efficient charge transport in optoelectronic devices. To address these limitations, this study proposes a BTO:TiO<sub>2</sub> composite film fabricated via a facile route. The role of TiO<sub>2</sub> NPs tightly embedded within the BTO matrix as charge-transport “inter-bridges” was systematically elucidated in relation to film morphology and optoelectrical properties. The resulting BTO:TiO<sub>2</sub> film exhibits reduced surface roughness, enhanced electron conductivity, and significantly improved UVB–C absorption, enabling its use as an efficient and stable photoabsorber for both narrow- and broadband UV photodetectors, thereby paving the way for numerous practical UV-sensing applications.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117981"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-02-18DOI: 10.1016/j.optmat.2026.117983
Li Xia , Zhenxu Lin , Haixia Wu , Jie Song , Kaitao Chen , Tianpei Qiu , Yi Zhang , Zewen Lin , Hongliang Li , Yanqing Guo , Chengjun Pan , Rui Huang
Achieving thickness-controlled perovskite microplates via chemical vapor deposition (CVD) is an effective approach to enhancing cavity optical feedback, which is crucial for realizing ultralow-threshold continuous-wave (CW) perovskite lasers. Here, we report the thickness-controlled synthesis of CsPbBr3 films/microplates via SnBr2-regulated crystallization by single-step CVD. The introduction of low-melting-point SnBr2 has assisted controllable crystallization dynamics of CsPbBr3 by inhibiting the chemical reaction process between CsBr and PbBr2, thereby optimizing nucleation density and crystal growth rate. The precise control of SnBr2 not only reduces the deposition rate and promotes grain growth in CsPbBr3 films/microplates, but also eliminates defect states within these structures. The resulting CsPbBr3 microplates possess high crystal quality and strong photoluminescence, while maintaining stability under continuous CW-laser illumination without observable photodegradation. Consequently, we achieved stable multi-mode whispering-gallery mode lasing with a low threshold of 153 W/cm2 under 405-nm laser excitation at room temperature. Our findings will open up multiple avenues for the design and fabrication of high-quality perovskites micro-crystals for CW-pumped perovskite lasers.
{"title":"Thickness controlled CsPbBr3 microplates by SnBr2-regulated crystallization for low-threshold continuous-wave pumped whispering gallery mode lasing","authors":"Li Xia , Zhenxu Lin , Haixia Wu , Jie Song , Kaitao Chen , Tianpei Qiu , Yi Zhang , Zewen Lin , Hongliang Li , Yanqing Guo , Chengjun Pan , Rui Huang","doi":"10.1016/j.optmat.2026.117983","DOIUrl":"10.1016/j.optmat.2026.117983","url":null,"abstract":"<div><div>Achieving thickness-controlled perovskite microplates via chemical vapor deposition (CVD) is an effective approach to enhancing cavity optical feedback, which is crucial for realizing ultralow-threshold continuous-wave (CW) perovskite lasers. Here, we report the thickness-controlled synthesis of CsPbBr<sub>3</sub> films/microplates via SnBr<sub>2</sub>-regulated crystallization by single-step CVD. The introduction of low-melting-point SnBr<sub>2</sub> has assisted controllable crystallization dynamics of CsPbBr<sub>3</sub> by inhibiting the chemical reaction process between CsBr and PbBr<sub>2,</sub> thereby optimizing nucleation density and crystal growth rate. The precise control of SnBr<sub>2</sub> not only reduces the deposition rate and promotes grain growth in CsPbBr<sub>3</sub> films/microplates, but also eliminates defect states within these structures. The resulting CsPbBr<sub>3</sub> microplates possess high crystal quality and strong photoluminescence, while maintaining stability under continuous CW-laser illumination without observable photodegradation. Consequently, we achieved stable multi-mode whispering-gallery mode lasing with a low threshold of 153 W/cm<sup>2</sup> under 405-nm laser excitation at room temperature. Our findings will open up multiple avenues for the design and fabrication of high-quality perovskites micro-crystals for CW-pumped perovskite lasers.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117983"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-27DOI: 10.1016/j.optmat.2026.117928
Sultan , Md.Zafer Alam , Mohammad Jane Alam , S.M. Afzal , Salman A. Khan , M.A.N. Razvi , Shabbir Ahmad , Alimuddin
Organic nonlinear optical (NLO) materials play a crucial role in advancing photonic and optoelectronic technologies due to their high optical nonlinearity, structural tunability, and ease of fabrication. Among them, donor–π–acceptor (D–π–A) systems based on indandione and chalcone scaffolds have exhibited remarkable third-order NLO responses, largely driven by efficient intramolecular charge transfer (ICT). In this work, we report the synthesis and comprehensive characterization of a novel methoxy-substituted indandione–chalcone derivative, (Z)-2-(2,5-dimethoxybenzylidene)-5-methoxy-2,3-dihydro-1H-inden-1-one (BMDI), prepared via base-catalyzed aldol condensation. Molecular structure was confirmed using FTIR, (1H and 13C) NMR, and high-resolution mass spectrometry analysis, while thermal stability was verified by the thermogravimetric analysis (TGA). Photophysical studies revealed pronounced π–π∗ transitions, strong solvatochromism, and enhanced fluorescence, underscoring the polarity-sensitive nature of the said molecule. The optical band gap (Eg) was estimated to be 3.53 eV. Third-order NLO properties, evaluated using the Z-scan technique, indicated saturable absorption (SA) and self-defocusing behaviour. The nonlinear refractive index (n2), absorption coefficient (β), and third-order susceptibility (χ(3)) were determined to be of the order of 10−8 cm2/W, 10−4 cm/W, and 10−6 esu, respectively. The nonlinear figure of merit highlights BMDI's potential for optical switching applications. Furthermore, density functional theory (DFT) calculations were performed to validate the experimental findings. Geometry optimization, FTIR, NMR, HOMO–LUMO energy gap, frontier molecular orbital (FMO) distributions, natural bond orbital (NBO) analysis, and NLO parameters were investigated at the B3LYP/6–311++G(d,p) level, while the absorption spectra were simulated using TD-DFT. Overall, BMDI emerges as a promising multifunctional chromophore for nonlinear photonics, optical sensing, and integrated optoelectronic systems.
{"title":"Exploring the photophysical and nonlinear optical properties of a methoxy-functionalized indandione-based chalcone derivative: Experimental and theoretical insights","authors":"Sultan , Md.Zafer Alam , Mohammad Jane Alam , S.M. Afzal , Salman A. Khan , M.A.N. Razvi , Shabbir Ahmad , Alimuddin","doi":"10.1016/j.optmat.2026.117928","DOIUrl":"10.1016/j.optmat.2026.117928","url":null,"abstract":"<div><div>Organic nonlinear optical (NLO) materials play a crucial role in advancing photonic and optoelectronic technologies due to their high optical nonlinearity, structural tunability, and ease of fabrication. Among them, donor–π–acceptor (D–π–A) systems based on indandione and chalcone scaffolds have exhibited remarkable third-order NLO responses, largely driven by efficient intramolecular charge transfer (ICT). In this work, we report the synthesis and comprehensive characterization of a novel methoxy-substituted indandione–chalcone derivative, <strong><em>(Z)-2-(2,5-dimethoxybenzylidene)-5-methoxy-2,3-dihydro-1H-inden-1-one</em> (BMDI)</strong>, prepared via base-catalyzed aldol condensation. Molecular structure was confirmed using FTIR, (<sup>1</sup>H and <sup>13</sup>C) NMR, and high-resolution mass spectrometry analysis, while thermal stability was verified by the thermogravimetric analysis (TGA). Photophysical studies revealed pronounced π–π∗ transitions, strong solvatochromism, and enhanced fluorescence, underscoring the polarity-sensitive nature of the said molecule. The optical band gap (<em>E</em><sub><em>g</em></sub>) was estimated to be 3.53 eV. Third-order NLO properties, evaluated using the Z-scan technique, indicated saturable absorption (SA) and self-defocusing behaviour. The nonlinear refractive index (<em>n</em><sub><em>2</em></sub>), absorption coefficient (<em>β</em>), and third-order susceptibility (<em>χ</em><sup><em>(3)</em></sup>) were determined to be of the order of 10<sup>−8</sup> cm<sup>2</sup>/W, 10<sup>−4</sup> cm/W, and 10<sup>−6</sup> esu, respectively. The nonlinear figure of merit highlights BMDI's potential for optical switching applications. Furthermore, density functional theory (DFT) calculations were performed to validate the experimental findings. Geometry optimization, FTIR, NMR, HOMO–LUMO energy gap, frontier molecular orbital (FMO) distributions, natural bond orbital (NBO) analysis, and NLO parameters were investigated at the B3LYP/6–311++G(d,p) level, while the absorption spectra were simulated using TD-DFT. Overall, BMDI emerges as a promising multifunctional chromophore for nonlinear photonics, optical sensing, and integrated optoelectronic systems.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117928"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-02-11DOI: 10.1016/j.optmat.2026.117959
L. Trinkler , D. Nilova , A. Sarakovskis , B. Berzina , Y.H. Hsiao , C.J. Chiang , Y.H. Shih , L. Chang , M.M.C. Chou
Excitation and relaxation processes of luminescence from bound excitons were studied in Cu2O thin films electrodeposited on copper substrate in comparison with those in Cu2O single crystal. Photoluminescence excitation was performed with a wavelength-tunable laser in the 10-300 K thermal range. The emission spectra contained the 1.72 eV, 1.53 eV and 1.36 eV emission bands due to , , centres, and additional bands at 1.63 and 1.80 eV ascribed to bound excitons localized at other defects. For the first time the photoluminescence excitation spectrum of bound excitons was obtained for the Cu2O thin films. It covers 1.8-3.0 eV energy range including the region of yellow/green/blue/violet excitons and a red band, corresponding to direct excitation of oxygen-vacancy-related centre. The shape of the luminescence thermal decay curves and variation of activation energy with temperature speak in favor of complex process of bound exciton relaxation. The differences in spectral properties of Cu2O thin films and single crystal are discussed.
{"title":"Excitation and relaxation of bound excitons in Cu2O thin films electrodeposited on Cu substrate","authors":"L. Trinkler , D. Nilova , A. Sarakovskis , B. Berzina , Y.H. Hsiao , C.J. Chiang , Y.H. Shih , L. Chang , M.M.C. Chou","doi":"10.1016/j.optmat.2026.117959","DOIUrl":"10.1016/j.optmat.2026.117959","url":null,"abstract":"<div><div>Excitation and relaxation processes of luminescence from bound excitons were studied in Cu<sub>2</sub>O thin films electrodeposited on copper substrate in comparison with those in Cu<sub>2</sub>O single crystal. Photoluminescence excitation was performed with a wavelength-tunable laser in the 10-300 K thermal range. The emission spectra contained the 1.72 eV, 1.53 eV and 1.36 eV emission bands due to <span><math><mrow><msubsup><mi>V</mi><mi>O</mi><mrow><mn>2</mn><mo>+</mo></mrow></msubsup></mrow></math></span>, <span><math><mrow><msubsup><mi>V</mi><mi>O</mi><mo>+</mo></msubsup></mrow></math></span>, <span><math><mrow><msub><mi>V</mi><mtext>Cu</mtext></msub></mrow></math></span> centres, and additional bands at 1.63 and 1.80 eV ascribed to bound excitons localized at other defects. For the first time the photoluminescence excitation spectrum of bound excitons was obtained for the Cu<sub>2</sub>O thin films. It covers 1.8-3.0 eV energy range including the region of yellow/green/blue/violet excitons and a red band, corresponding to direct excitation of oxygen-vacancy-related centre. The shape of the luminescence thermal decay curves and variation of activation energy with temperature speak in favor of complex process of bound exciton relaxation. The differences in spectral properties of Cu<sub>2</sub>O thin films and single crystal are discussed.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117959"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147384677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-03-02DOI: 10.1016/j.optmat.2026.118002
Sivasankar Parameswaran , Ananthan Alagumalai , Nivethitha Ganesan , Amal Krishna , Senthil A. Gurusamy Thangavelu , V. Sudha , Sai Muthukumar Vijayasayee , Ananthanarayanan Krishnamoorthy
Nonlinear optical absorption (NLA) is a cornerstone phenomenon driving transformative innovations across optoelectronics, biophotonics, and nanophotonics. In this study, we have designed and rigorously evaluated two new pull-push-push-pull symmetric A-D-D-A fluorophores featuring phenothiazine as the central donor (D) moiety, paired with either N-ethyl dicyanomethylene rhodanine (SS1) or dicyanomethylene indanone (SS2) as terminal acceptor (A) moieties. This strategic substitution of the acceptor moiety profoundly reshaped their photophysical and nonlinear optical behavior. SS2 fluorophore exhibited an impressive ∼100 nm red-shift in both absorption and emission spectra, coupled with a narrow optical bandgap of 1.71 eV, and a remarkably high extinction coefficient of 4.49 × 105 M−1 cm−1 significantly outperforming the SS1 fluorophore. Using nanosecond Z-scan measurements at 532 nm, SS2 demonstrated a substantially higher effective excited state absorption (ESA) than SS1. The nonlinear absorption coefficient (γ) of SS2 reached 74 × 10−24 m3/W2, with a Figure of Merit (FOM = σex/σg) of 17.53 over an order of magnitude greater than SS1's γ of 5 × 10−24 m3/W2 and FOM of 1.69. This remarkable enhancement in SS2 stems from the powerful electron-withdrawing capability of the dicyanomethylene indanone acceptor, which induces a large quadrupole moment within the A-D-D-A architecture and Density Functional Theory (DFT) calculations corroborated these findings. Leveraging SS2's superior excited state absorption, we demonstrated its outstanding optical power limiting capabilities. With an optical limiting threshold (OLT) of 0.77 J/cm2 at 80% linear transmittance, SS2 surpasses many existing organic push-pull fluorophores, positioning it as a leading candidate for protecting photonic devices.
{"title":"Strategic terminal-group tuning of symmetric A-D-D-A fluorophores enhances nonlinear absorption and optical limiting for photonic applications","authors":"Sivasankar Parameswaran , Ananthan Alagumalai , Nivethitha Ganesan , Amal Krishna , Senthil A. Gurusamy Thangavelu , V. Sudha , Sai Muthukumar Vijayasayee , Ananthanarayanan Krishnamoorthy","doi":"10.1016/j.optmat.2026.118002","DOIUrl":"10.1016/j.optmat.2026.118002","url":null,"abstract":"<div><div>Nonlinear optical absorption (NLA) is a cornerstone phenomenon driving transformative innovations across optoelectronics, biophotonics, and nanophotonics. In this study, we have designed and rigorously evaluated two new pull-push-push-pull symmetric A-D-D-A fluorophores featuring phenothiazine as the central donor (D) moiety, paired with either N-ethyl dicyanomethylene rhodanine (SS1) or dicyanomethylene indanone (SS2) as terminal acceptor (A) moieties. This strategic substitution of the acceptor moiety profoundly reshaped their photophysical and nonlinear optical behavior. SS2 fluorophore exhibited an impressive ∼100 nm red-shift in both absorption and emission spectra, coupled with a narrow optical bandgap of 1.71 eV, and a remarkably high extinction coefficient of 4.49 × 10<sup>5</sup> M<sup>−1</sup> cm<sup>−1</sup> significantly outperforming the SS1 fluorophore. Using nanosecond Z-scan measurements at 532 nm, SS2 demonstrated a substantially higher effective excited state absorption (ESA) than SS1. The nonlinear absorption coefficient (γ) of SS2 reached 74 × 10<sup>−24</sup> m<sup>3</sup>/W<sup>2</sup>, with a Figure of Merit (FOM = σ<sub>ex</sub>/σ<sub>g</sub>) of 17.53 over an order of magnitude greater than SS1's γ of 5 × 10<sup>−24</sup> m<sup>3</sup>/W<sup>2</sup> and FOM of 1.69. This remarkable enhancement in SS2 stems from the powerful electron-withdrawing capability of the dicyanomethylene indanone acceptor, which induces a large quadrupole moment within the A-D-D-A architecture and Density Functional Theory (DFT) calculations corroborated these findings. Leveraging SS2's superior excited state absorption, we demonstrated its outstanding optical power limiting capabilities. With an optical limiting threshold (OLT) of 0.77 J/cm<sup>2</sup> at 80% linear transmittance, SS2 surpasses many existing organic push-pull fluorophores, positioning it as a leading candidate for protecting photonic devices.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 118002"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147384772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A series of undoped and Dy3+ activated Gd3GaO6 phosphors was synthesized via solution combustion approach followed by annealing at 1450 °C to improve crystallinity. Powder XRD, FESEM and EDX techniques were employed to analyze crystal structure, surface characteristics and chemical composition, respectively. XRD results confirmed orthorhombic phase with Cmc21 space group and corresponds well with standard JCPDS data. FESEM images revealed agglomerated nature of particles with size lying in nanometer range. Composition of constituent elements of prepared phosphor was determined by EDX study. As observed from photoluminescence data, phosphors exhibit dominant yellow emission at 572 nm (4F9/2 → 6H13/2) and moderate blue emission at 488 nm (4F9/2 → 6H15/2) demonstrating Dy3+ ions are situated at low symmetry sites. Significant decrease in luminescence intensity was observed at 4 mol % Dy3+ in GGO lattice ascribed to non-radiative energy transfer occurring between adjacent Dy3+ ions. Photometric results including measurements of chromaticity coordinates and CCT values (<4500 K) validates yellow emission indicating the use of prepared phosphors in WLEDs to produce yellow light.
{"title":"Orthorhombic Gd3GaO6:Dy3+ nanophosphors with tunable luminescence: Structural, morphological and photometric insights for WLEDs","authors":"Reshu Kajal , Devender Singh , Rinki Jangra , Bharti Dahiya , Meghna Kadian , Pawan Kumar , Ramesh Kumar , Harish Kumar","doi":"10.1016/j.optmat.2026.117942","DOIUrl":"10.1016/j.optmat.2026.117942","url":null,"abstract":"<div><div>A series of undoped and Dy<sup>3+</sup> activated Gd<sub>3</sub>GaO<sub>6</sub> phosphors was synthesized <em>via</em> solution combustion approach followed by annealing at 1450 °C to improve crystallinity. Powder XRD, FESEM and EDX techniques were employed to analyze crystal structure, surface characteristics and chemical composition, respectively. XRD results confirmed orthorhombic phase with Cmc2<sub>1</sub> space group and corresponds well with standard JCPDS data. FESEM images revealed agglomerated nature of particles with size lying in nanometer range. Composition of constituent elements of prepared phosphor was determined by EDX study. As observed from photoluminescence data, phosphors exhibit dominant yellow emission at 572 nm (<sup>4</sup>F<sub>9/2</sub> → <sup>6</sup>H<sub>13/2</sub>) and moderate blue emission at 488 nm (<sup>4</sup>F<sub>9/2</sub> → <sup>6</sup>H<sub>15/2</sub>) demonstrating Dy<sup>3+</sup> ions are situated at low symmetry sites. Significant decrease in luminescence intensity was observed at 4 mol % Dy<sup>3+</sup> in GGO lattice ascribed to non-radiative energy transfer occurring between adjacent Dy<sup>3+</sup> ions. Photometric results including measurements of chromaticity coordinates and CCT values (<4500 K) validates yellow emission indicating the use of prepared phosphors in WLEDs to produce yellow light.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"174 ","pages":"Article 117942"},"PeriodicalIF":4.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147384777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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